Public Member Functions | |
| c4_Cursor (c4_Sequence &, int) | |
| Construct a new cursor. | |
| c4_RowRef | operator * () const |
| Dereference this cursor to "almost" a row. | |
| c4_RowRef | operator[] (int) const |
| This is the same as *(cursor + offset). | |
| c4_Cursor & | operator++ () |
| Pre-increment the cursor. | |
| c4_Cursor | operator++ (int) |
| Post-increment the cursor. | |
| ref= | operator-- () |
| Pre-decrement the cursor. | |
| ref= | operator-- (int) |
| Post-decrement the cursor. | |
| c4_Cursor & | operator+= (int) |
| Advance by a given offset. | |
| c4_Cursor & | operator-= (int) |
| Back up by a given offset. | |
| c4_Cursor | operator- (int) const |
| Subtract a specified offset. | |
| int | operator- (c4_Cursor) const |
| Return the distance between two cursors. | |
Public Attributes | |
| c4_Sequence * | _seq |
| Pointer to the sequence. | |
| int | _index |
| Current index into the sequence. | |
Friends | |
| c4_Cursor | operator+ (c4_Cursor, int) |
| Add specified offset. | |
| c4_Cursor | operator+ (int, c4_Cursor) |
| Add specified offset to cursor. | |
| bool | operator== (c4_Cursor, c4_Cursor) |
| Return true if both cursors are equal. | |
| bool | operator!= (c4_Cursor, c4_Cursor) |
| Return true if both cursors are not equal. | |
| bool | operator< (c4_Cursor, c4_Cursor) |
| True if first cursor is less than second cursor. | |
| bool | operator> (c4_Cursor, c4_Cursor) |
| True if first cursor is greater than second cursor. | |
| bool | operator<= (c4_Cursor, c4_Cursor) |
| True if first cursor is less or equal to second cursor. | |
| bool | operator>= (c4_Cursor, c4_Cursor) |
| True if first cursor is greater or equal to second cursor. | |
| bool | operator== (const c4_RowRef &, const c4_RowRef &) |
| Return true if the contents of both rows are equal. | |
| bool | operator!= (const c4_RowRef &, const c4_RowRef &) |
| Return true if the contents of both rows are not equal. | |
| bool | operator< (const c4_RowRef &, const c4_RowRef &) |
| True if first row is less than second row. | |
| bool | operator> (const c4_RowRef &, const c4_RowRef &) |
| True if first row is greater than second row. | |
| bool | operator<= (const c4_RowRef &, const c4_RowRef &) |
| True if first row is less or equal to second row. | |
| bool | operator>= (const c4_RowRef &, const c4_RowRef &) |
| True if first row is greater or equal to second row. | |
Cursor objects can be used to point to specific entries in a view. A cursor acts very much like a pointer to a row in a view, and is returned when taking the address of a c4_RowRef. Dereferencing a cursor leads to the original row reference again. You can construct a cursor for a c4_Row, but since such rows are not part of a collection, incrementing or decrementing these cursors is meaningless (and wrong).
The usual range of pointer operations can be applied to these objects: pre/post-increment and decrement, adding or subtracting integer offsets, as well as the full range of comparison operators. If two cursors point to entries in the same view, their difference can be calculated.
As with regular pointers, care must be taken to avoid running off of either end of a view (the debug build includes assertions to check this).
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Construct a new cursor. Cursor cannot be created without an underlying view, but you could define a global "nullView" object and then initialize the cursor with "&nullView[0]". This works because cursors need not point to a valid row. |